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Hoyal Cuthill JF, Lloyd GT. Measuring homoplasy I: comprehensive measures of maximum and minimum cost under parsimony across discrete cost matrix character types. Cladistics 2024. [PMID: 38924583 DOI: 10.1111/cla.12582] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Revised: 04/19/2024] [Accepted: 04/24/2024] [Indexed: 06/28/2024] Open
Abstract
Here, we propose, prove mathematically and discuss maximum and minimum measures of maximum parsimony evolution across 12 discrete phylogenetic character types, classified across 4467 morphological and molecular datasets. Covered character types are: constant, binary symmetric, multistate unordered (non-additive) symmetric, multistate linear ordered symmetric, multistate non-linear ordered symmetric, binary irreversible, multistate irreversible, binary Dollo, multistate Dollo, multistate custom symmetric, binary custom asymmetric and multistate custom asymmetric characters. We summarize published solutions and provide and prove a range of new formulae for the algebraic calculation of minimum (m), maximum (g) and maximum possible (gmax) character cost for applicable character types. Algorithms for exhaustive calculation of m, g and gmax applicable to all classified character types (within computational limits on the numbers of taxa and states) are also provided. The general algorithmic solution for minimum steps (m) is identical to a minimum spanning tree on the state graph or minimum weight spanning arborescence on the state digraph. Algorithmic solutions for character g and gmax are based on matrix mathematics equivalent to optimization on the star tree, respectively for given state frequencies and all possible state frequencies meeting specified numbers of taxa and states. We show that maximizing possible cost (gmax) with given transition costs can be equivalent to maximizing, across all possible state frequency combinations, the lowest implied cost of state transitions if any one state is ancestral on the star tree, via the solution of systems of linear equations. The methods we present, implemented in the Claddis R package, extend to a comprehensive range, the fundamental character types for which homoplasy may be measured under parsimony using m, g and gmax, including extra cost (h), consistency index (ci), retention index (ri) or indices based thereon.
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2
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Smith TJ, Sansom RS, Pisani D, Donoghue PCJ. Fossilization can mislead analyses of phenotypic disparity. Proc Biol Sci 2023; 290:20230522. [PMID: 37554036 PMCID: PMC10410227 DOI: 10.1098/rspb.2023.0522] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Accepted: 07/20/2023] [Indexed: 08/10/2023] Open
Abstract
Analyses of morphological disparity can incorporate living and fossil taxa to facilitate the exploration of how phenotypic variation changes through time. However, taphonomic processes introduce non-random patterns of data loss in fossil data and their impact on perceptions of disparity is unclear. To address this, we characterize how measures of disparity change when simulated and empirical data are degraded through random and structured data loss. We demonstrate that both types of data loss can distort the disparity of clades, and that the magnitude and direction of these changes varies between the most commonly employed distance metrics and disparity indices. The inclusion of extant taxa and exceptionally preserved fossils mitigates these distortions and clarifies the full extent of the data lost, most of which would otherwise go uncharacterized. This facilitates the use of ancestral state estimation and evolutionary simulations to further control for the effects of data loss. Where the addition of such reference taxa is not possible, we urge caution in the extrapolation of general patterns in disparity from datasets that characterize subsets of phenotype, which may represent no more than the traits that they sample.
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Affiliation(s)
- Thomas J. Smith
- Bristol Palaeobiology Group, School of Earth Sciences, University of Bristol, Life Sciences Building, Tyndall Avenue, Bristol BS8 1TQ, UK
- Department of Earth Sciences, University of Oxford, South Parks Road, Oxford OX1 3AN, UK
| | - Robert S. Sansom
- Department of Earth and Environmental Sciences, University of Manchester, Williamson Building, Oxford Road, Manchester M13 9PL, UK
| | - Davide Pisani
- Bristol Palaeobiology Group, School of Earth Sciences, University of Bristol, Life Sciences Building, Tyndall Avenue, Bristol BS8 1TQ, UK
| | - Philip C. J. Donoghue
- Bristol Palaeobiology Group, School of Earth Sciences, University of Bristol, Life Sciences Building, Tyndall Avenue, Bristol BS8 1TQ, UK
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4
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Evolution and dispersal of snakes across the Cretaceous-Paleogene mass extinction. Nat Commun 2021; 12:5335. [PMID: 34521829 PMCID: PMC8440539 DOI: 10.1038/s41467-021-25136-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2018] [Accepted: 07/22/2021] [Indexed: 02/08/2023] Open
Abstract
Mass extinctions have repeatedly shaped global biodiversity. The Cretaceous-Paleogene (K-Pg) mass extinction caused the demise of numerous vertebrate groups, and its aftermath saw the rapid diversification of surviving mammals, birds, frogs, and teleost fishes. However, the effects of the K-Pg extinction on the evolution of snakes-a major clade of predators comprising over 3,700 living species-remains poorly understood. Here, we combine an extensive molecular dataset with phylogenetically and stratigraphically constrained fossil calibrations to infer an evolutionary timescale for Serpentes. We reveal a potential diversification among crown snakes associated with the K-Pg mass extinction, led by the successful colonisation of Asia by the major extant clade Afrophidia. Vertebral morphometrics suggest increasing morphological specialisation among marine snakes through the Paleogene. The dispersal patterns of snakes following the K-Pg underscore the importance of this mass extinction event in shaping Earth's extant vertebrate faunas.
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5
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Cashmore DD, Butler RJ, Maidment SCR. Taxonomic identification bias does not drive patterns of abundance and diversity in theropod dinosaurs. Biol Lett 2021; 17:20210168. [PMID: 34256583 PMCID: PMC8278044 DOI: 10.1098/rsbl.2021.0168] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
The ability of palaeontologists to correctly diagnose and classify new fossil species from incomplete morphological data is fundamental to our understanding of evolution. Different parts of the vertebrate skeleton have different likelihoods of fossil preservation and varying amounts of taxonomic information, which could bias our interpretations of fossil material. Substantial previous research has focused on the diversity and macroevolution of non-avian theropod dinosaurs. Theropods provide a rich dataset for analysis of the interactions between taxonomic diagnosability and fossil preservation. We use specimen data and formal taxonomic diagnoses to create a new metric, the Likelihood of Diagnosis, which quantifies the diagnostic likelihood of fossil species in relation to bone preservation potential. We use this to assess whether a taxonomic identification bias impacts the non-avian theropod fossil record. We find that the patterns of differential species abundance and clade diversity are not a consequence of their relative diagnosability. Although there are other factors that bias the theropod fossil record that are not investigated here, our results suggest that patterns of relative abundance and diversity for theropods might be more representative of Mesozoic ecology than often considered.
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Affiliation(s)
- Daniel D Cashmore
- School of Geography, Earth and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - Richard J Butler
- School of Geography, Earth and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - Susannah C R Maidment
- School of Geography, Earth and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK.,Department of Earth Sciences, Natural History Museum, Cromwell Road, London SW7 5BD, UK
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6
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Callender-Crowe LM, Sansom RS. Osteological characters of birds and reptiles are more congruent with molecular phylogenies than soft characters are. Zool J Linn Soc 2021. [DOI: 10.1093/zoolinnean/zlaa136] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Abstract
Despite increased use of genomic data in phylogenetics, morphological information remains vital for resolving evolutionary relationships, particularly for fossil taxa. The properties and models of evolution of molecular sequence data are well characterized and mature, relative to those of morphological data. Furthermore, heterogeneity, integration and relative homoplasy of empirical morphological data could prove problematic for phylogenetic reconstruction. Here we compare osteological and non-osteological characters of 28 morphological datasets of extant saurians in terms of their homoplasy relative to molecular trees. Analysis of individual avian datasets finds osteological characters to be significantly more consistent with molecular data than soft characters are. Significant differences between morphological partitions were also observed in the age at which characters resolved on molecular trees. Osteological character changes occur relatively earlier in deep branches, whilst soft-tissue character transitions are more recent in shallow branches. The combined results demonstrate differences in evolutionary dynamics between morphological partitions. This may reflect evolutionary constraints acting on osteological characters, compared with the relative lability of soft characters. Furthermore, it provides some support to phylogenetic interpretations of fossil data, including dinosaurs, which are predominately osteological. Recent advances in amphibian and mammal phylogenetics may make these patterns possible to test for all tetrapods.
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Affiliation(s)
- Leah M Callender-Crowe
- The University of Manchester, Department of Earth and Environmental Sciences, Manchester, UK
- School of Biological Sciences, University of Reading, Reading, UK
| | - Robert S Sansom
- The University of Manchester, Department of Earth and Environmental Sciences, Manchester, UK
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Neumann JS, Desalle R, Narechania A, Schierwater B, Tessler M. Morphological Characters Can Strongly Influence Early Animal Relationships Inferred from Phylogenomic Data Sets. Syst Biol 2021; 70:360-375. [PMID: 32462193 PMCID: PMC7875439 DOI: 10.1093/sysbio/syaa038] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Revised: 01/27/2020] [Accepted: 01/29/2020] [Indexed: 12/19/2022] Open
Abstract
There are considerable phylogenetic incongruencies between morphological and phylogenomic data for the deep evolution of animals. This has contributed to a heated debate over the earliest-branching lineage of the animal kingdom: the sister to all other Metazoa (SOM). Here, we use published phylogenomic data sets ($\sim $45,000-400,000 characters in size with $\sim $15-100 taxa) that focus on early metazoan phylogeny to evaluate the impact of incorporating morphological data sets ($\sim $15-275 characters). We additionally use small exemplar data sets to quantify how increased taxon sampling can help stabilize phylogenetic inferences. We apply a plethora of common methods, that is, likelihood models and their "equivalent" under parsimony: character weighting schemes. Our results are at odds with the typical view of phylogenomics, that is, that genomic-scale data sets will swamp out inferences from morphological data. Instead, weighting morphological data 2-10$\times $ in both likelihood and parsimony can in some cases "flip" which phylum is inferred to be the SOM. This typically results in the molecular hypothesis of Ctenophora as the SOM flipping to Porifera (or occasionally Placozoa). However, greater taxon sampling improves phylogenetic stability, with some of the larger molecular data sets ($>$200,000 characters and up to $\sim $100 taxa) showing node stability even with $\geqq100\times $ upweighting of morphological data. Accordingly, our analyses have three strong messages. 1) The assumption that genomic data will automatically "swamp out" morphological data is not always true for the SOM question. Morphological data have a strong influence in our analyses of combined data sets, even when outnumbered thousands of times by molecular data. Morphology therefore should not be counted out a priori. 2) We here quantify for the first time how the stability of the SOM node improves for several genomic data sets when the taxon sampling is increased. 3) The patterns of "flipping points" (i.e., the weighting of morphological data it takes to change the inferred SOM) carry information about the phylogenetic stability of matrices. The weighting space is an innovative way to assess comparability of data sets that could be developed into a new sensitivity analysis tool. [Metazoa; Morphology; Phylogenomics; Weighting.].
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Affiliation(s)
- Johannes S Neumann
- Richard Gilder Graduate School, American Museum of Natural History, New York, NY 10024, USA
- Division of Invertebrate Zoology, American Museum of Natural History, New York, NY 10024, USA
- Sackler Institute for Comparative Genomics, American Museum of Natural History, New York, NY 10024, USA
| | - Rob Desalle
- Division of Invertebrate Zoology, American Museum of Natural History, New York, NY 10024, USA
- Sackler Institute for Comparative Genomics, American Museum of Natural History, New York, NY 10024, USA
| | - Apurva Narechania
- Sackler Institute for Comparative Genomics, American Museum of Natural History, New York, NY 10024, USA
| | - Bernd Schierwater
- Division of Invertebrate Zoology, American Museum of Natural History, New York, NY 10024, USA
- Sackler Institute for Comparative Genomics, American Museum of Natural History, New York, NY 10024, USA
- ITZ, Division of Ecology and Evolution, Tierärztliche Hochschule Hannover, Bünteweg 9, 30559 Hannover, Germany
| | - Michael Tessler
- Division of Invertebrate Zoology, American Museum of Natural History, New York, NY 10024, USA
- Sackler Institute for Comparative Genomics, American Museum of Natural History, New York, NY 10024, USA
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8
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Celik MA, Phillips MJ. Conflict Resolution for Mesozoic Mammals: Reconciling Phylogenetic Incongruence Among Anatomical Regions. Front Genet 2020; 11:0651. [PMID: 32774343 PMCID: PMC7381353 DOI: 10.3389/fgene.2020.00651] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2019] [Accepted: 05/28/2020] [Indexed: 11/13/2022] Open
Abstract
The evolutionary history of Mesozoic mammaliaformes is well studied. Although the backbone of their phylogeny is well resolved, the placement of ecologically specialized groups has remained uncertain. Functional and developmental covariation has long been identified as an important source of phylogenetic error, yet combining incongruent morphological characters altogether is currently a common practice when reconstructing phylogenetic relationships. Ignoring incongruence may inflate the confidence in reconstructing relationships, particularly for the placement of highly derived and ecologically specialized taxa, such as among australosphenidans (particularly, crown monotremes), haramiyidans, and multituberculates. The alternative placement of these highly derived clades can alter the taxonomic constituency and temporal origin of the mammalian crown group. Based on prior hypotheses and correlated homoplasy analyses, we identified cheek teeth and shoulder girdle character complexes as having a high potential to introduce phylogenetic error. We showed that incongruence among mandibulodental, cranial, and postcranial anatomical partitions for the placement of the australosphenidans, haramiyids, and multituberculates could largely be explained by apparently non-phylogenetic covariance from cheek teeth and shoulder girdle characters. Excluding these character complexes brought agreement between anatomical regions and improved the confidence in tree topology. These results emphasize the importance of considering and ameliorating major sources of bias in morphological data, and we anticipate that these will be valuable for confidently integrating morphological and molecular data in phylogenetic and dating analyses.
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Affiliation(s)
- Mélina A. Celik
- School of Biology and Environmental Science, Queensland University of Technology, Brisbane, QLD, Australia
| | - Matthew J. Phillips
- School of Biology and Environmental Science, Queensland University of Technology, Brisbane, QLD, Australia
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Li Y, Ruta M, Wills MA. Craniodental and Postcranial Characters of Non-Avian Dinosauria Often Imply Different Trees. Syst Biol 2020; 69:638-659. [PMID: 31769837 PMCID: PMC7302058 DOI: 10.1093/sysbio/syz077] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2018] [Revised: 11/08/2019] [Accepted: 11/18/2019] [Indexed: 12/28/2022] Open
Abstract
Despite the increasing importance of molecular sequence data, morphology still makes an important contribution to resolving the phylogeny of many groups, and is the only source of data for most fossils. Most systematists sample morphological characters as broadly as possible on the principle of total evidence. However, it is not uncommon for sampling to be focused on particular aspects of anatomy, either because characters therein are believed to be more informative, or because preservation biases restrict what is available. Empirically, the optimal trees from partitions of morphological data sets often represent significantly different hypotheses of relationships. Previous work on hard-part versus soft-part characters across animal phyla revealed significant differences in about a half of sampled studies. Similarly, studies of the craniodental versus postcranial characters of vertebrates revealed significantly different trees in about one-third of cases, with the highest rates observed in non-avian dinosaurs. We test whether this is a generality here with a much larger sample of 81 published data matrices across all major dinosaur groups. Using the incongruence length difference test and two variants of the incongruence relationship difference test, we found significant incongruence in about 50% of cases. Incongruence is not uniformly distributed across major dinosaur clades, being highest (63%) in Theropoda and lowest (25%) in Thyreophora. As in previous studies, our partition tests show some sensitivity to matrix dimensions and the amount and distribution of missing entries. Levels of homoplasy and retained synapomorphy are similar between partitions, such that incongruence must partly reflect differences in patterns of homoplasy between partitions, which may itself be a function of modularity and mosaic evolution. Finally, we implement new tests to determine which partition yields trees most similar to those from the entire matrix. Despite no bias across dinosaurs overall, there are striking differences between major groups. The craniodental characters of Ornithischia and the postcranial characters of Saurischia yield trees most similar to the "total evidence" trees derived from the entire matrix. Trees from these same character partitions also tend to be most stratigraphically congruent: a mutual consilience suggesting that those partitions yield more accurate trees. [Dinosauria; homoplasy; partition homogeneity.].
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Affiliation(s)
- Yimeng Li
- Department of Biology & Biochemistry, The Milner Centre for Evolution, The University of Bath, The Avenue, Claverton Down, Bath BA2 7AY, UK
| | - Marcello Ruta
- School of Life Sciences, University of Lincoln, Joseph Banks Laboratories, Green Lane, Lincoln LN6 7DL, UK
| | - Matthew A Wills
- Department of Biology & Biochemistry, The Milner Centre for Evolution, The University of Bath, The Avenue, Claverton Down, Bath BA2 7AY, UK
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10
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Koch NM, Parry LA. Death is on Our Side: Paleontological Data Drastically Modify Phylogenetic Hypotheses. Syst Biol 2020; 69:1052-1067. [DOI: 10.1093/sysbio/syaa023] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Revised: 03/02/2020] [Accepted: 03/17/2020] [Indexed: 12/11/2022] Open
Abstract
Abstract
Fossils are the only remaining evidence of the majority of species that have ever existed, providing a direct window into events in evolutionary history that shaped the diversification of life on Earth. Phylogenies underpin our ability to make sense of evolution but are routinely inferred using only data available from living organisms. Although extinct taxa have been shown to add crucial information for inferring macroevolutionary patterns and processes (such as ancestral states, paleobiogeography and diversification dynamics), the role fossils play in reconstructing phylogeny is controversial. Since the early years of phylogenetic systematics, different studies have dismissed the impact of fossils due to their incompleteness, championed their ability to overturn phylogenetic hypotheses or concluded that their behavior is indistinguishable from that of extant taxa. Based on taxon addition experiments on empirical data matrices, we show that the inclusion of paleontological data has a remarkable effect in phylogenetic inference. Incorporating fossils often (yet not always) induces stronger topological changes than increasing sampling of extant taxa. Fossils also produce unique topological rearrangements, allowing the exploration of regions of treespace that are never visited by analyses of only extant taxa. Previous studies have proposed a suite of explanations for the topological behavior of fossils, such as their retention of unique morphologies or their ability to break long branches. We develop predictive models that demonstrate that the possession of distinctive character state combinations is the primary predictor of the degree of induced topological change, and that the relative impact of taxa (fossil and extant) can be predicted to some extent before any phylogenetic analysis. Our results bolster the consensus of recent empirical studies by showing the unique role of paleontological data in phylogenetic inference, and provide the first quantitative assessment of its determinants, with broad consequences for the design of taxon sampling in both morphological and total-evidence analyses. [phylogeny, morphology, fossils, parsimony, Bayesian inference.]
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Affiliation(s)
- Nicolás Mongiardino Koch
- Department of Geology & Geophysics, Yale University, 210 Whitney Avenue, New Haven, CT 06510, USA
| | - Luke A Parry
- Department of Geology & Geophysics, Yale University, 210 Whitney Avenue, New Haven, CT 06510, USA
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11
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Sookias RB. Exploring the effects of character construction and choice, outgroups and analytical method on phylogenetic inference from discrete characters in extant crocodilians. Zool J Linn Soc 2019. [DOI: 10.1093/zoolinnean/zlz015] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Abstract
Phylogenies for fossil taxa must be inferred from morphology, but accuracy of inference is questionable. Here, morphological characters for extant crocodilians are investigated to assess how to improve inference accuracy. The homoplasy of characters is assessed against a DNA-based phylogenetic tree. Cranial characters are significantly less homoplastic, but this result is perhaps confounded by research effort. Meristic characters are significantly more homoplastic and should be used with caution. Characters were reassessed first hand and documented. Those characters passing tests of robust construction are significantly less homoplastic. Suggestions are made for means to improve coding of discrete characters. Phylogenies inferred using only robust characters and a reassessed matrix, including corrected scorings, were not overall closer to the DNA tree, but did often place the gharial (Gavialis) in a position agreeing with or closer to it. The effects of the choice of analytical method were modest, but Bayesian analysis of the reassessed matrix placed Gavialis and Mecistops (slender-snouted crocodile) in DNA-concordant positions. Use of extant rather than extinct outgroups, even with the original matrix, placed Gavialis in a more DNA-concordant position, as did factoring out 3D skull shape. The morphological case for placement of Gavialis outside other extant crocodilians is arguably overstated, with many characters linked to skull shape.
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Affiliation(s)
- Roland B Sookias
- Museum für Naturkunde, Leibniz-Institut für Evolutions- und Biodiversitätsforschung, Invalidenstraße, Berlin, Germany
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12
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Brinkworth AR, Sansom R, Wills MA. Phylogenetic incongruence and homoplasy in the appendages and bodies of arthropods: why broad character sampling is best. Zool J Linn Soc 2019. [DOI: 10.1093/zoolinnean/zlz024] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
Abstract
Notwithstanding the rapidly increasing sampling density of molecular sequence data, morphological characters still make an important contribution to our understanding of the evolutionary relationships of arthropod groups. In many clades, characters relating to the number and morphological specialization of appendages are ascribed particular phylogenetic significance and may be preferentially sampled. However, previous studies have shown that partitions of morphological character matrices often imply significantly different phylogenies. Here, we ask whether a similar incongruence is observed in the appendage and non-appendage characters of arthropods. We apply tree length (incongruence length difference, ILD) and tree distance (incongruence relationship difference, IRD) tests to these partitions in an empirical sample of 53 published neontological datasets for arthropods. We find significant incongruence about one time in five: more often than expected, but markedly less often than in previous partition studies. We also find similar levels of homoplasy in limb and non-limb characters, both in terms of internal consistency and consistency relative to molecular trees. Taken together, these findings imply that sampled limb and non-limb characters are of similar phylogenetic utility and quality, and that a total evidence approach to their analysis is preferable.
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Affiliation(s)
- Andrew R Brinkworth
- The Milner Centre for Evolution, Department of Biology and Biochemistry, The University of Bath, Claverton Down, Bath, UK
| | - Robert Sansom
- School of Earth and Environmental Science, The University of Manchester, Manchester, UK
| | - Matthew A Wills
- The Milner Centre for Evolution, Department of Biology and Biochemistry, The University of Bath, Claverton Down, Bath, UK
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13
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Abstract
Biologists would be mistaken if they relegated living fossils to paleontological inquiry or assumed that the concept is dead. It is now used to describe entities ranging from viruses to higher taxa, despite recent warnings of misleading inferences. Current work on character evolution illustrates how analyzing living fossils and stasis in terms of parts (characters) and wholes (e.g., organisms and lineages) advances our understanding of prolonged stasis at many hierarchical levels. Instead of viewing the concept's task as categorizing living fossils, we show how its primary role is to mark out what is in need of explanation, accounting for the persistence of both molecular and morphological traits. Rethinking different conceptions of living fossils as specific hypotheses reveals novel avenues for research that integrate phylogenetics, ecological and evolutionary modeling, and evo-devo to produce a more unified theoretical outlook.
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Affiliation(s)
- Scott Lidgard
- Integrative Research Center, Field Museum, Chicago, Illinois
| | - Alan C Love
- Department of Philosophy and the Minnesota Center for Philosophy of Science, University of Minnesota, Minneapolis
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14
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Sansom RS, Choate PG, Keating JN, Randle E. Parsimony, not Bayesian analysis, recovers more stratigraphically congruent phylogenetic trees. Biol Lett 2018; 14:20180263. [PMID: 29925561 PMCID: PMC6030593 DOI: 10.1098/rsbl.2018.0263] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Accepted: 05/19/2018] [Indexed: 11/12/2022] Open
Abstract
Reconstructing evolutionary histories requires accurate phylogenetic trees. Recent simulation studies suggest that probabilistic phylogenetic analyses of morphological data are more accurate than traditional parsimony techniques. Here, we use empirical data to compare Bayesian and parsimony phylogenies in terms of their congruence with the distribution of age ranges of the component taxa. Analysis of 167 independent morphological data matrices of fossil tetrapods finds that Bayesian trees exhibit significantly lower stratigraphic congruence than the equivalent parsimony trees. As such, taking stratigraphic data as an independent benchmark indicates that parsimony analyses are more accurate for phylogenetic reconstruction of morphological data. The discrepancy between simulated and empirical studies may result from historic data peaking practices or some complexities of empirical data as yet unaccounted for.
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Affiliation(s)
- Robert S Sansom
- School of Earth and Environmental Sciences, University of Manchester, Manchester M13 9PT, UK
| | - Peter G Choate
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester M13 9PT, UK
| | - Joseph N Keating
- School of Earth and Environmental Sciences, University of Manchester, Manchester M13 9PT, UK
| | - Emma Randle
- School of Earth and Environmental Sciences, University of Manchester, Manchester M13 9PT, UK
- Department of Biology and Biochemistry, University of Bath, Bath BA2 7AY, UK
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15
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Pyron RA. Novel Approaches for Phylogenetic Inference from Morphological Data and Total-Evidence Dating in Squamate Reptiles (Lizards, Snakes, and Amphisbaenians). Syst Biol 2018; 66:38-56. [PMID: 28173602 DOI: 10.1093/sysbio/syw068] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2015] [Revised: 07/12/2016] [Accepted: 07/20/2016] [Indexed: 02/04/2023] Open
Abstract
Here, I combine previously underutilized models and priors to perform more biologically realistic phylogenetic inference from morphological data, with an example from squamate reptiles. When coding morphological characters, it is often possible to denote ordered states with explicit reference to observed or hypothetical ancestral conditions. Using this logic, we can integrate across character-state labels and estimate meaningful rates of forward and backward transitions from plesiomorphy to apomorphy. I refer to this approach as MkA, for “asymmetric.” The MkA model incorporates the biological reality of limited reversal for many phylogenetically informative characters, and significantly increases likelihoods in the empirical data sets. Despite this, the phylogeny of Squamata remains contentious. Total-evidence analyses using combined morphological and molecular data and the MkA approach tend toward recent consensus estimates supporting a nested Iguania. However, support for this topology is not unambiguous across data sets or analyses, and no mechanism has been proposed to explain the widespread incongruence between partitions, or the hidden support for various topologies in those partitions. Furthermore, different morphological data sets produced by different authors contain both different characters and different states for the same or similar characters, resulting in drastically different placements for many important fossil lineages. Effort is needed to standardize ontology for morphology, resolve incongruence, and estimate a robust phylogeny. The MkA approach provides a preliminary avenue for investigating morphological evolution while accounting for temporal evidence and asymmetry in character-state changes.
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Affiliation(s)
- R Alexander Pyron
- Department of Biological Sciences, The George Washington University, 2023 G St. NW, Washington, DC, USA
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16
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Sansom RS, Wills MA. Differences between hard and soft phylogenetic data. Proc Biol Sci 2017; 284:20172150. [PMID: 29237859 PMCID: PMC5745416 DOI: 10.1098/rspb.2017.2150] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Accepted: 11/15/2017] [Indexed: 11/20/2022] Open
Abstract
When building the tree of life, variability of phylogenetic signal is often accounted for by partitioning gene sequences and testing for differences. The same considerations, however, are rarely applied to morphological data, potentially undermining its use in evolutionary contexts. Here, we apply partition heterogeneity tests to 59 animal datasets to demonstrate that significant differences exist between the phylogenetic signal conveyed by 'hard' and 'soft' characters (bones, teeth and shells versus myology, integument etc). Furthermore, the morphological partitions differ significantly in their consistency relative to independent molecular trees. The observed morphological differences correspond with missing data biases, and as such their existence presents a problem not only for phylogeny reconstruction, but also for interpretations of fossil data. Evolutionary inferences drawn from clades in which hard, readily fossilizable characters are relatively less consistent and different from other morphology (mammals, bivalves) may be less secure. More secure inferences might be drawn from the fossil record of clades that exhibit fewer differences, or exhibit more consistent hard characters (fishes, birds). In all cases, it will be necessary to consider the impact of missing data on empirical data, and the differences that exist between morphological modules.
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Affiliation(s)
- Robert S Sansom
- School of Earth and Environmental Sciences, University of Manchester, Manchester M13 9PT, UK
| | - Matthew A Wills
- Milner Centre for Evolution, Department of Biology and Biochemistry, University of Bath, Bath BA2 7AY, UK
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17
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Parry LA, Baron MG, Vinther J. Multiple optimality criteria support Ornithoscelida. ROYAL SOCIETY OPEN SCIENCE 2017; 4:170833. [PMID: 29134086 PMCID: PMC5666269 DOI: 10.1098/rsos.170833] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/05/2017] [Accepted: 09/25/2017] [Indexed: 06/07/2023]
Abstract
A recent study of early dinosaur evolution using equal-weights parsimony recovered a scheme of dinosaur interrelationships and classification that differed from historical consensus in a single, but significant, respect; Ornithischia and Saurischia were not recovered as monophyletic sister-taxa, but rather Ornithischia and Theropoda formed a novel clade named Ornithoscelida. However, these analyses only used maximum parsimony, and numerous recent simulation studies have questioned the accuracy of parsimony under equal weights. Here, we provide additional support for this alternative hypothesis using Bayesian implementation of the Mkv model, as well as through number of additional parsimony analyses, including implied weighting. Using Bayesian inference and implied weighting, we recover the same fundamental topology for Dinosauria as the original study, with a monophyletic Ornithoscelida, demonstrating that the main suite of methods used in morphological phylogenetics recover this novel hypothesis. This result was further scrutinized through the systematic exclusion of different character sets. Novel characters from the original study (those not taken or adapted from previous phylogenetic studies) were found to be more important for resolving the relationships within Dinosauromorpha than the relationships within Dinosauria. Reanalysis of a modified version of the character matrix that supports the Ornithischia-Saurischia dichotomy under maximum parsimony also supports this hypothesis under implied weighting, but not under the Mkv model, with both Theropoda and Sauropodomorpha becoming paraphyletic with respect to Ornithischia.
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Affiliation(s)
- Luke A. Parry
- Bristol Life Sciences Building, University of Bristol, 24 Tyndall Avenue, Bristol BS8 1TH, UK
- Department of Earth Sciences, Natural History Museum, London, Cromwell Road, London SW7 5BD, UK
| | - Matthew G. Baron
- Department of Earth Sciences, Natural History Museum, London, Cromwell Road, London SW7 5BD, UK
- Department of Earth Science, University of Cambridge, Downing Street, Cambridge CB2 3EQ, UK
| | - Jakob Vinther
- Bristol Life Sciences Building, University of Bristol, 24 Tyndall Avenue, Bristol BS8 1TH, UK
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18
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Sansom RS, Wills MA, Williams T. Dental Data Perform Relatively Poorly in Reconstructing Mammal Phylogenies: Morphological Partitions Evaluated with Molecular Benchmarks. Syst Biol 2017; 66:813-822. [PMID: 28003534 PMCID: PMC5790133 DOI: 10.1093/sysbio/syw116] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2016] [Revised: 11/30/2016] [Accepted: 12/20/2016] [Indexed: 01/27/2023] Open
Abstract
Phylogenetic trees underpin reconstructions of evolutionary history and tests of evolutionary hypotheses. They are inferred from both molecular and morphological data, yet the relative value of morphology has been questioned in this context due to perceived homoplasy, developmental linkage, and nonindependence of characters. Nevertheless, fossil data are limited to incomplete subsets of preserved morphology, and different regions are treated as equivalent. Through meta-analysis of 40 data sets, we show here that the dental and osteological characters of mammals convey significantly different phylogenetic signals, and that osteological characters are significantly more compatible with molecular trees. Furthermore, the application of simplified paleontological filters (retaining only dental data) results in significantly greater loss of phylogenetic signal than random character ablation. Although the mammal fossil record is largely comprised of teeth, dental data alone are generally found to be less reliable for phylogenetic reconstruction given their incongruence with osteological and molecular data. These findings highlight the need for rigorous meta-analyses of distributions of homoplasy in morphological data. These tests, and consequent refinements to phylogenetic analyses that they permit, promise to improve the quality of all macroevolutionary studies that hinge on accurate trees. [Homoplasy; Mammalia; morphology; osteology; phylogeny; teeth.
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Affiliation(s)
- Robert S. Sansom
- School of Earth and Environmental Sciences, University of Manchester, Oxford Road, Manchester M13 9PT, UK
| | - Matthew Albion Wills
- Department of Biology and Biochemistry, University of Bath, Claverton Down, Bath BA2 7AY, UK
| | - Tamara Williams
- School of Earth and Environmental Sciences, University of Manchester, Oxford Road, Manchester M13 9PT, UK
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19
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Kear BP, Aplin KP, Westerman M. Bandicoot fossils and DNA elucidate lineage antiquity amongst xeric-adapted Australasian marsupials. Sci Rep 2016; 6:37537. [PMID: 27881865 PMCID: PMC5121598 DOI: 10.1038/srep37537] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Accepted: 10/31/2016] [Indexed: 11/09/2022] Open
Abstract
Bandicoots (Peramelemorphia) are a unique order of Australasian marsupials whose sparse fossil record has been used as prima facie evidence for climate change coincident faunal turnover. In particular, the hypothesized replacement of ancient rainforest-dwelling extinct lineages by antecedents of xeric-tolerant extant taxa during the late Miocene (~10 Ma) has been advocated as a broader pattern evident amongst other marsupial clades. Problematically, however, this is in persistent conflict with DNA phylogenies. We therefore determine the pattern and timing of bandicoot evolution using the first combined morphological + DNA sequence dataset of Peramelemorphia. In addition, we document a remarkably archaic new fossil peramelemorphian taxon that inhabited a latest Quaternary mosaic savannah-riparian forest ecosystem on the Aru Islands of Eastern Indonesia. Our phylogenetic analyses reveal that unsuspected dental homoplasy and the detrimental effects of missing data collectively obscure stem bandicoot relationships. Nevertheless, recalibrated molecular clocks and multiple ancestral area optimizations unanimously infer an early diversification of modern xeric-adapted forms. These probably originated during the late Palaeogene (30-40 Ma) alongside progenitors of other desert marsupials, and thus occupied seasonally dry heterogenous habitats long before the onset of late Neogene aridity.
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Affiliation(s)
- Benjamin P Kear
- Museum of Evolution, Uppsala University, Norbyvägen 16, SE-752 36 Uppsala, Sweden.,Department of Earth Sciences, Uppsala University, Villavägen 16, SE-752 36 Uppsala, Sweden
| | - Ken P Aplin
- Division of Mammals, National Museum of Natural History, Smithsonian Institution, P.O. Box. 37012, Washington, DC, 20013-7012, USA
| | - Michael Westerman
- Department of Ecology, Environment and Evolution, La Trobe University, Melbourne, Victoria 3086, Australia
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